The present invention relates to a powered handpiece for driving surgical blades. More particularly, it relates to a liquid cooled, powered surgical handpiece for use in driving a surgical blade assembly, such as a surgical drill.
Powered handpieces are commonly used in many medical specialties to drive surgical blades for performing various diverse cutting functions including resection, dissection, debridement, shaving, drilling, pulverizing, and shaping of anatomical tissue. In the areas of ENT/head/neck surgery, powered or motorized handpieces and systems are commonly connected to a surgical cutting instrument including an outer tubular member forming a cutting window at a distal end thereof, and an inner blade member coaxially disposed within the outer tubular member. The inner blade assembly terminates at a distal cutting tip. With this configuration, the powered handpiece rotates and/or oscillates the inner blade member relative to the outer tubular member so as to cause the distal cutting tip to perform a desired cutting operation. Alternatively, a more conventional micro-drill bit having a cutting tip can also be connected to, and be driven by, the powered handpiece. Regardless, because the cutting procedures associated with ENT/head/neck surgery are highly delicate, yet require numerous cutting motions or rotations by the cutting tip to complete the procedure, the powered handpiece greatly decreases procedure time requirements and the physical drain on the surgeon.
Undoubtedly, surgical powered handpieces used in combination with micro-cutting instruments are highly beneficial. As with any motor, however, operation of a powered handpiece generates heat. This is especially true for ENT/head/neck procedures where the motor associated with the surgical handpiece is required to operate at highly elevated speeds. Because the surgeon directly handles the powered handpiece, over time the generated heat can cause distinct hand discomfort. This is especially true during prolonged procedures. Obviously, any distractions may negatively affect the surgeon""s performance.
Powered surgical handpieces continue to be highly useful with surgical micro-cutting instruments, especially bone drilling instruments. However, the heat generated by the powered handpiece can lead to user discomfort and may limit usefulness of the device. Therefore, a need exists for a powered surgical handpiece incorporating a cooling system.
One aspect of the present invention provides a powered surgical handpiece for use with a micro-cutting instrument, especially a bone-drilling device useful for ENT/head/neck procedures. The powered surgical handpiece includes a motor contained within a housing. The housing includes a motor enclosure surrounding the motor and a sleeve placed about the motor enclosure. At least a portion of the sleeve has an inner diameter greater than an outer diameter of a corresponding portion of the motor enclosure, such that the housing defines an internal gap or passage. Finally, the sleeve forms inlet and outlet ports that are fluidly connected to the internal passage. During use, a cooling fluid, such as de-ionized water or saline, is forced into the internal passage via the inlet port. The motor is sealed relative to the cooling fluid by the motor enclosure. Thus, the cooling fluid does not directly contact the motor, but instead serves as a heat exchange medium through which heat generated by the motor is thermally transferred to the cooling fluid via the motor enclosure. The now heated fluid exits the housing at the outlet port. As a result of the thermal transfer of heat from the motor to the cooling fluid, and the subsequent evacuation of the now-heated fluid away from the handpiece, heat transfer to an outer surface of the housing, otherwise handled by the surgeon, is minimized. In an alternative embodiment, the housing is configured to define a serpentined or specifically routed internal fluid path to optimize heat transfer.